A loop of the above kind conventionally comprises a compressor, a condenser, a desiccant cartridge, an expansion unit and an evaporator through which a cooling fluid flows in the above order. A flow of air to be directed to the passenger compartment flows through the evaporator.
The operational status of the air-conditioning loop of the motor vehicle must be checked, in particular during periodic servicing.
There are various possible causes of malfunctioning of the loop and it is essential to be able to identify them in order to correct them.
One prior art diagnostic device measures the pressure of the cooling fluid at the outlet from the compressor (high pressure side) and the prevailing temperature in the passenger compartment under reproducible conditions.
However, the above prior art device can establish only an outline diagnosis without full identification of the nature and the origin of the malfunction that has been noted.